1,404 research outputs found
An Analysis of Juvenile Chinook Salmon Outmigration Speed and Survival in Response to Habitat Features: Sacramento River from Knights Landing to Sacramento, California
Outmigration is an important life stage for Chinook salmon (Oncorhynchus tshawytscha) survival in the Sacramento River, and yet our understanding of their behavior and needs during this time is limited. To gain a better understanding of their survival and movement rates during outmigration, late fall run Chinook salmon smolts were tracked using acoustic telemetry techniques. Habitat features were measured and quantified throughout the study area to evaluate how Chinook salmon respond to key levee features including shade, instream woody material, and aquatic vegetation. The overall average movement speed through the entire study area was 0.77 m/s with an overall survival of 86%. Based on multiple linear regressions, vegetation was found to have the largest effect on speed with fish slowing down with increased vegetation cover. Shade, river mile, and velocity also had significant effects on movement speeds, but instream woody material was not significant. The result for woody material was surprising since it was anticipated to have a large impact on movement speeds. A positive correlation was found between faster fish movement speeds and higher survival. No evidence of diel movement patterns was found after releasing the fish. These finding can help managers create sites better designed to help Chinook salmon in the Sacramento River system. Results from this paper indicate that the type of woody material being installed might not be appropriate for this life stage of salmon
Enhanced hippocampal long-term potentiation and spatial learning in aged 11ß-hydroxysteroid dehydrogenase type 1 knock-out mice
Glucocorticoids are pivotal in the maintenance of memory and cognitive functions as well as other essential physiological processes including energy metabolism, stress responses, and cell proliferation. Normal aging in both rodents and humans is often characterized by elevated glucocorticoid levels that correlate with hippocampus-dependent memory impairments. 11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) amplifies local intracellular ("intracrine") glucocorticoid action; in the brain it is highly expressed in the hippocampus. We investigated whether the impact of 11ß-HSD1 deficiency in knock-out mice (congenic on C57BL/6J strain) on cognitive function with aging reflects direct CNS or indirect effects of altered peripheral insulin-glucose metabolism. Spatial learning and memory was enhanced in 12 month "middle-aged" and 24 month "aged" 11ß-HSD1<sup>–/–</sup> mice compared with age-matched congenic controls. These effects were not caused by alterations in other cognitive (working memory in a spontaneous alternation task) or affective domains (anxiety-related behaviors), to changes in plasma corticosterone or glucose levels, or to altered age-related pathologies in 11ß-HSD1<sup>–/–</sup> mice. Young 11ß-HSD1<sup>–/–</sup> mice showed significantly increased newborn cell proliferation in the dentate gyrus, but this was not maintained into aging. Long-term potentiation was significantly enhanced in subfield CA1 of hippocampal slices from aged 11ß-HSD1<sup>–/–</sup> mice. These data suggest that 11ß-HSD1 deficiency enhances synaptic potentiation in the aged hippocampus and this may underlie the better maintenance of learning and memory with aging, which occurs in the absence of increased neurogenesis
Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects
Introduction: A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether g-loop dysfunction contributes to AMI in people with knee joint OA.
Methods: Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the g-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t
tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration.
Results: Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG
amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554).
Conclusions: g-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population
Measuring Streambank Erosion: A Comparison of Erosion Pins, Total Station, and Terrestrial Laser Scanner
Streambank erosion is diffcult to quantify; models and field methods are needed to assess this important sediment source to streams. Our objectives were to (1) evaluate and compare three techniques for quantifying streambank erosion: erosion pins, total station, and laser scanning, (2) spatially assess streambank erosion rates in the Indian Mill Creek watershed of Michigan, USA, and (3) relate results with modeling of nonpoint source pollution. We found large absolute and relative errors between the different measurement techniques. However, we were unable to determine any statistically significant differences between techniques and only observed a correlation between total station and laser scanner. This suggests that the three methods have limited comparability and differences between measurements were largely not systemic. Further, the application of each technique should be dependent on site conditions, project goals, desired resolution, and resources. The laser scanner collected high-resolution data on clear, barren streambanks, but the erosion pin and total station were more representative of complex vegetated banks. Streambank erosion rates varied throughout the watershed and were influenced by fluvial processes. We estimate that streambank erosion contributed 28.5% of the creek’s total sediment load. These findings are important to address sources of watershed impairments related to sedimentation, as choosing an applicable technique for individual purposes can help reduce the challenges and costs of a streambank erosion study
Foot Pain, Impairment and Disability in Patients With Acute Gout Flares; A Prospective Observational Study
Objectives: The aim of this study was to evaluate the impact of acute gout on foot pain, impairment and disability. Methods: This prospective observational study recruited 20 patients with acute gout flares. Patients were recruited from emergency departments, hospital wards and rheumatology outpatient clinics throughout Auckland, New Zealand. Patients were recruited at the time of the flare (baseline visit) and then reassessed at a follow-up visit once the acute flare had resolved 6-8 weeks after the initial assessment. Joint counts, C-reactive protein and serum urate were recorded at both visits. General and foot-specific outcome measures were also recorded at each visit including pain visual analogue scale, Health Assessment Questionnaire (HAQ)-II, Lower Limb Tasks Questionnaire, and the Leeds Foot Impact Scale. Results: The foot was affected by acute gout in 14 (70%) patients. Objective measures of joint inflammation including swollen and tender joint counts and C-reactive protein significantly improved at the follow-up visit, compared with the baseline visit. At baseline, high levels of foot pain, impairment and disability were reported. All patient-reported outcome measures of general and foot-specific musculoskeletal function improved at the follow-up visit compared with the baseline visit. However, pain, impairment and disability scores did not entirely normalise after resolution of the acute gout flare. Conclusions: Patients with acute gout flares experience severe foot pain, impairment and disability. These data provide further support for improved management of gout to prevent the consequences of poorly controlled disease
Reducing effects of dispersal on the bias of 2-sample mark-recapture estimators of stream fish abundance
The 2-sample mark-recapture method with Chapman’s estimator is often used by inland fishery managers to estimate the reach-scale abundance of stream fish. An important assumption of this method is that no dispersal into or out of the study reach occurs between the two samples. Violations of this assumption are probably common in practice, but their effect on bias (systematic error) of abundance estimates is poorly understood, especially in small populations. Estimation methods permitting dispersal exist but, for logistical reasons, often are infeasible for routine assessments in streams. The purpose of this paper is to extend available results regarding effects of dispersal on the bias of Chapman’s estimator as applied to reach-scale studies of stream fish abundance. We examine for the first time the joint effects of dispersal and sampling variation on the bias of this estimator. To reduce the bias effects of dispersal, we propose a modified sampling scheme in which the original study reach is expanded, a central subreach is sampled during the mark session (sample 1), and the entire reach is sampled during the recapture session (sample 2). This modified sampling scheme can substantially reduce bias effects of dispersal without requiring unique marking of individual fish or additional site visits. Analytical and simulation results show that sampling variation tends to create negative bias with respect to study-reach abundance, while dispersal tends to create positive bias; the net effect can be positive, negative, or zero, depending on the true abundance, capture probabilities, and amount and nature of dispersal. In most cases, simply expanding the study reach is an effective way to reduce dispersal-related bias of Chapman’s estimator, but expanding the study reach and employing the modified sampling scheme we propose is a better alternative for accurately estimating abundance with the same level of sampling effort
The footwear experiences of people wth Gout- a qualitative study
Abstract Background: Footwear is an important concern for people with gout, who often describe difficulty finding suitable footwear. Previous studies have identified footwear as a major concern for people with gout. The aim of this study was to carry out an exploration of the footwear experiences of people with gout. Methods: A qualitative descriptive methodological approach was used for both data collection and analysis. A purposive sampling strategy was adopted with semi-structured interviews conducted, involving 11 participants with gout. Thematic analysis was employed to identify key meanings and patterns within the data. Results: Four key themes derived from interviews included; (1) comfort as a priority, (2) knowing what to buy, (3) knowing what to wear, and (4) challenges of different environments. Footwear comfort was of great importance and linked to characteristics of footwear, with uncomfortable footwear negatively influencing participation in daily activities. The balancing of comfort, appearance and cost, led to less options and reduced confidence when shoe shopping. Footwear use was further limited by the presence of foot tophi and flares, resulting in compromise of footwear choice. Environments such as formal settings and the workplace, led to different footwear requirements. Conclusion: People with gout experience problems with footwear which can impact many aspects of life. Health care professionals should consider these footwear-related issues to help facilitate those with gout in finding appropriate footwear. Keywords: Gout, Footwear, Qualitative researc
Assessing the quality of written information provision for surgical procedures:A case study in oesophagectomy
OBJECTIVE: To examine the content and quality of written information provided by surgical centres for patients undergoing oesophagectomy for cancer. DESIGN: Cross-sectional study of the content of National Health Service (NHS) patient information leaflets (PILs) about oesophageal cancer surgery, using a modified framework approach. DATA SOURCES: Written information leaflets from 41 of 43 cancer centres undertaking surgery for oesophageal cancer in England and Wales (response rate 95.3%). ELIGIBILITY CRITERIA: All English language versions of PILs about oesophagectomy. RESULTS: 32 different PILs were identified, of which 2 were generic tools (Macmillan ‘understanding cancer of the gullet’ and EIDO ‘oesophagectomy’). Although most PILs focused on describing in-hospital adverse events, information varied widely and was often misleading. Just 1 leaflet described survival benefits of surgery and 2 mentioned the possibility of disease recurrence. CONCLUSIONS: Written information provided for patients by NHS cancer centres undertaking oesophagectomy is inconsistent and incomplete. It is recommended that surgeons work together with patients to agree on standards of information provision of relevance to all stakeholders’ needs
Viral Studies In Pemphigus
Sera from patients with pemphigus. other bullous dermatoses, and various control groups were examined to determine whether paramyxoviruses, particularly SVS and DU, could be isolated. Indirect immunofluorescent tests and virus neutralization tests were employed to determine the incidence of SV5 virus antibody in sera from patients with various dermatoses, and to determine whether antibody to SV5 was related to the antiepithelial antibody associated with pemphigus. The frequency of antibody to SV5 (9%) and DU (11%) virus in sera from patients with pemphigus was not higher than the frequency ot antibodies to SV5 (14%) and DU (17%) in sera of various control groups. The absence of antibodies to 8V5 and DU virus in sera from most patients with pemphigus, the absence of intercellular antiepithelial antibody in sets from dogs and most humans with antibody to SV5 and DU virus, and the absence of correlation of titers in a patient with both types of antibody indicate that SV5 antibody is not functionally related to “pemphigus antibody.” In addition, no SV5, DU, or other hemadsorbing paramyxovirus was isolated from sera of patients with pemphigus. Isolation from blister fluid was not attempted. Infection with SV5, DU, or similar paramyxovirus is probably not usually, if at all, related to the etiology of non-Brazilian pemphigus
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